Process of making acetate dyestuff powders



United States Patent PROCESS OF MAKING ACETATE DYESTUFF POWDERS WilliamH. Armento, Albany, and Joseph Bianco, Troy,

N. Y., assignors to General Aniline & Film Corporation, New York, N. Y.,a corporation of Delaware No Drawing. Application December 30, 1952,Serial No. 328,799

9 Claims. (Cl. 8-58) This invention relates to a dyestufi composition inthe form of a finely divided powder of improved dispersibility and tothe method of producing same.

It is well known in the prior art to mill dyestulf compositions withshearing forces to reduce the particle size of the dyestufi. Suchdyestulf compositions frequently contain surface active agents and otheradditives. Following the milling operation the composition, which is inthe form of a thick magma, is then removed from the mill, usually afterhaving been fluidized by the addition of water thereto. This compositionis then dried in pans in vacuo at elevated temperatures, after which thecomposition is subjected to an additional grinding operation to break upthe agglomeration which occurs during drying. Such prior art methods arewell exemplified by U. S. Patents Nos. 2,079,548 and 2,181,800 andReissue Patent No. 21,402.

Such prior art methods involve several manipulative steps and the use ofseveral different types of equipment which is disadvantageous forseveral reasons, among which are loss of time, increased expenses forlabor and equipment, loss of materials and final product in theequipment due to incomplete transfer, increased hazards in handling,etc. The addition of fluid to the milled composition to facilitate itsremoval to the drying pans is a wasteful step since the fluid added mustbe subsequently removed in the drying operation. Further theagglomeration occurring during the drying in the vacuum pans is almostalways not completely compensated for in the subsequent grindingoperation.

It is an object of this invention to provide a dyestufl composition ofimproved dispersibility which is capable of dyeing fibrous materialssuch as acetate rayon and synthetic polymeric material such as nylon,Orlon, Acrilan, Dacron, Dynel, and the like, in level shadessubstantially free of spotting and the like.

Another object of this invention is to provide dye compositions in theform of highly dispersible soft fine powders which do not agglomerate toharder and larger particles diflicult to disperse. i 1

A further object of this invention is to provide an improved method forproducing such dyestuff composi tions. Other objects and advantages willappear as the description proceeds.

The aforementioned objects are obtained by-the instant invention whichcomprises milling with shearing forces, a thick magma comprising thedyestuff, a-solid dispersing agent and preferably a small amount ofa-neutral or alkaline acting salt until the desired particle size isobtained, and then drying the composition in the mill to a powder byapplying a vacuum thereto without the addition of heat while continuingthe milling action. The

dyestuff powder composition is then ready for standardization by mixingin usual manner with diluents, bulking agents and the like.

It will be seen that the process of this invention is highly economicaland. eficient in eliminating various steps heretofore practiced: Thedyestuif powder thus directly produced is in most cases in bettercondition than the powders heretofore produced since the agglomerationusually occurring during drying is avoided. The vacuum treatment in themill in conjunction with the continued milling action and its concurrentfinite generation of heat in situ due to friction is sufiicient to drythe composition to a powder without the addition of heat in view of thefact that new surfaces are thereby constantly being exposed to optimumdrying conditions.

In carrying out the milling operation, the dyestufl? composition must bein the form of a stifi' paste or thick magma, whereby the mixer exerts ashearing action on the dye particles to produce a uniform dispersion ofparticles of the desired size. Generally, the mixer is a and neutral oralkaline acting salt.

Werner-Plleiderer or Day kneading machine or a Banbury mixer.

In order for the dyestuif composition to have the required consistencyfor -mil ling with shearing forces, it should have a total solidscontent (before application of the vacuum. treatment of about 60 to 85%.Usually, it is suflicient to employ the dyestuff paste as it comesdirectly from the filter press, with a solids content of as low as toand mix it with dry dispersing agent Where .the initial consistency istoo thick, it--will be understood that water may be added to give thecomposition the consistency required for milling with shearing forces.Where the initial consistency of the'composition is too thin due to 1too low a solids content, as in some of the examples here- 'inafter setforth, if will be understood that the excess moisture will be rapidlyevaporated during the initial stages of the milling operation wherebythe composition then being milled will have the required 60 to 85%solids content. The usual proportions by weight of dry ingredicuts inthe dyestutf composition are about 40 to 60 parts of the dyestutl, to 40parts of dispersing agent and 0 to 10 parts of neutral or alkalineacting salt. The initial milling operation usually takes about 6 to 8hours,

7 after whichvacuum is applied to the mill to remove the remaining waterin the mix while continuing the milling action. The vacuum treatmentnormally takes about 2 to 4 hours, at the completion of which thecomposition is in the form of adry powder ready for standardization.

As dispersing agents any of the usual solid dispersing agents may beemployed as for example, sodium lignin sulfonate, oleoyl methyl taurinesodium salt, naphthalene sodium sulfonate, sodium alkylnaphthalenesulfonate, sodium oleyl sulfate, N,N-diethyl-N'-oleoyl-ethylene diaminehydrochloride, and the like.

As neutral or alkaline acting salts there may be employed sodiumcarbonate, sodium sulfate, sodium chloride, potassium pyrophosphate,sodium phosphate, potassium chloride, sodium pyrophosphate, magnesiumsulfate, magnesium chloride, calcium sulfate, and the like. In

-' general, such salts are alkali metal and alkaline earth metal saltsof strong or weak acids. However, salts having an alkaline reaction arepreferably employed. These are generally alkali metal salts of weakacids, for example, sodium carbonate. Such salts increase the dispersing3: efiiciency of the dispersing agent, prevent the formation of'disperseddyestufl' compositions which are low melting and tend tosinter, regulate pH and act as diluents or bulking agents in the finalcomposition.

While the process of this invention may be employed to treat anydyestuff in particulate form to thereby yield a finely divideddispersible powder, it is particularly advantageous when employed fortreating those insoluble dispersible dyestuffs used in dyeing acetaterayon and the synthetic polymericfibers such as nylon, Orlo-n, Aerilan,Dynel, Dacron: an'd'the like. The following dyestuffs which have beenfound particularly, amenable to treatment in accordance with the instantinvention are listed for illustrative purposes only.

C iHiO H 01130.0 HNQN:

CEHAOH The following specific examples, in' which parts-.are'by weightunless otherwise indicated; arev given for'rillustrative 5purposesnonlyl 6 Example 1 50 parts dye as a paste direct from thefilter 'press (60- solidicontent). offthe formula:

are p mixed in aEWerner" and: Pfieiderert mixer with: 47

parts sodium lignin sulfonate and 2% parts sodium car- '5 bonate. Themix is viscous milled for aboutohours. A vacuum then is applied andmilling continued until the powder is dry. It is removed from the mixerand standardized as usual. r 7

Example 2 I i 50 parts dye as a paste direct from the filter (70-75%solid content), of the formula:

OCHs.

Example 3 60 parts dye as a paste direct from the filter (35-40% solidcontent) of the formula:

and 40 parts sodium alkylnaphthalenesulfonate are viscous milled in aWerner and Pfleiderer mixer for 8 hours. A vacuum is then applied andmilling continued until the powder is dry. It is removed from the mixerand standardized as usual.

Example 4 50 parts dye as a paste direct from the filter (35-4071 solidcontent) of the formula:

S HO

are mixed in a Werner and Pileiderer mill with 47% parts sodium ligninsulfonate and 2% parts sodium carbonate for 6 hours. A vacuum is thenapplied and milling continued until the powder is dry, after which thepowder is removed from the mixer and standardized.

Example 5 50 parts dye as a paste direct from the filter (45-50% solidcontent) of the formula:

are mixed in a Werner and Pfleiderer mill with 47% parts sodium ligninsulfonate and 2% parts sodium carbonate. The charge is viscous milledfor 6 hours. A vacuum is then applied and milling continued until thepowder is dry. It is removed from the mixer and standardized as usual.

Example 6 50 parts dye as a paste direct from the filter (45-50% solidcontent) of the formula:

ensign: @Nwmmmi are viscous milled in a Werner and Pfleiderer mill for 8hours, with 50 parts sodium alkylnaphthalenesulfonate. A vacuum is thenapplied and milling continued until the powder is dry. It is removedfrom the mixer and standardized as usual.

Various modifications and variations of this invention will be obviousto a person skilled in the art and such variations and modifications areto be regarded as within the purview of this application and the spiritand scope of the appended claims.

We claim: 1

1. A process comprising milling with forces predominantly shearing innature a composition having a total solids content of about 60 topercent comprising an insoluble, dispersible, acetate type dyestutf, asolid dispersing agent, and water in an amount suificient to produce athick magma, and then drying the milled composition in the mill bysubjecting it to a vacuum treatment without the addition of heat whilecontinuing .the milling action.

2. A process comprising milling with forces predominantly shearing innature a composition having a total solids content of about 60 to 85percent comprising an insoluble, dispersible, acetate type dyestuif, asolid dispersing agent, a compound of the group consisting of theinorganic salts of alkali metals and alkaline earth metals, and water inan amount suificient to produce a thick magma, and then drying themilled composition in the mill by subjecting .it to a vacuum treatmentwithout the addition of heat while continuing the milling action.

3. The process of claim 2 in which the said compound is an alkalineacting salt.

4. The process of claim 3 in which said compound is sodium carbonate.

5. A process comprising milling with forces predominantly shearing innature a composition having a total solids content of about 60 to 85%and comprising, by weight, 50 parts of a dyestufl of the formula 47 /2parts of sodium lignin sulfonate and 2 /2 parts of sodium carbonate forabout 6 hours and then drying the milled composition in the mill bysubjecting it to a vacuum treatment without the addition of heat Whilecontinuing the milling action.

6. A process comprising milling with forces predominantly shearing innature a composition having a total solids content of about 60 to 85%and comprising, by weight, 50 parts of a dyestuif of the formula OCH:

O OH

47 /2 parts of oleoyl methyl taurine sodium salt and 2 /2 parts ofsodium pyrophosphate for about 6 hours, and then drying the milledcomposition in the mill by subjecting it to a vacuum treatment withoutthe addition of heat while continuing the milling action.

7. A process comprising milling with forces predominantly shearing innature, a composition having a total solids content of about 60 to 85%and comprising, by weight, 60 parts of a dyestutf of the formula and 40parts of sodium alkyl naphthalene sulfonate for about 8 hours, and thendrying the milled composition in the mill by subjecting it to a vacuumtreatment without the addition of heat while continuing the millingaction.

8. A process comprising milling with forces predominantly shearing innature a composition having a total 02 50 1 H S HO 47 /2 parts ofsodiumlignin sulfonate and 2 /2 parts of sodium carbonate for about 6 hoursand then drying the milled composition in the mill by subjecting it to avacuum treatment without the addition of heat While continuing themilling action.

9. A process comprising milling with forces predominantly shearing innature a composition having a total solids content of about 60 to 85%and comprising, by weight, 50 parts of .a dyestuff of the formula 47 /2parts of sodium lignin sulfonate and 2 /2 parts of sodiumcarbonate forabout 6 hours and then drying the milled composition in the mill bysubjecting it to a vacuum treatment without the addition of heat whilecontinuing the milling action.

References Cited in the tile of this patent UNITED STATES PATENTS213,471 Toufiiin Mar. 18, 1879 1,718,184 Ostermann June 18, 19291,837,772 Hailwood Dec. 22, 1931 2,065,762 Stanley Dec. 29, 19362,090,511 Crossley Aug. 17, 1939 2,181,800 Crossley Nov. 28, 1939

1. A PROCESS COMPRISING MILLING WITH FORCES PREDOMINANTLY SHEARING INNATURE A COMPOSITION HAVING A TOTAL SOLIDS CONTENT OF ABOUT 60 TO 85PERCENT COMPRISING AN INSOLUBLE, DISPERSIBLE, ACETATE TYPE DYESTUFF, ASOLID DISPERSING AGENT, AND WATER IN AN AMOUNT SUFFICIENT TO PRODUCE ATHICK MAGMA, AND THEN DRYING THE MILLED COMPOSITION IN THE MILL BYSUBJECTING IT TO A VACUUM TREATMENT WITHOUT THE ADDITION OF HEAT WHILECONTINUING THE MILLING ACTION.